July 12, 2011 -- Anorexia is the most lethal psychiatric disorder, carrying a sixfold increased risk of death -- four times the death risk from major depression.

The odds are even worse for people first diagnosed with anorexia in their 20s. They have 18 times the death risk of healthy people their age, according to an analysis of the medical literature by Jon Arcelus, MD, PhD, of the University of Leicester, England, and colleagues.

The study found anorexia to carry twice the death risk of schizophrenia and three times the death risk of bipolar disorder. Although anorexia is by far the deadliest eating disorder, death rates are also higher than normal in people with bulimia and "eating disorder not otherwise specified" (EDNOS, a common diagnosis for people with a mixture of atypical anorexia and atypical bulimia).

"Mortality rates in individuals with eating disorders are high not only for those with anorexia but also for those with EDNOS and bulimia, which highlights the seriousness of these conditions," Arcelus and colleagues conclude in the July issue of Archives of General Psychiatry.

The Arcelus study is based on analysis of data collected in 36 different studies published between 1966 and 2010. After adjusting death rates for sample size, the researchers calculate:

5.1 deaths per 1,000 people with anorexia per year. Anorexia increased death risk 5.86-fold.

1.7 deaths per 1,000 people with bulimia per year. Bulimia increased death risk 1.93-fold.

3.3 deaths per 1,000 people with EDNOS per year. EDNOS increased death risk 1.92-fold.

Bulimia and EDNOS carry significant risk. But Arcelus and colleagues note that people with anorexia often become bulimic, but then are at high risk of relapsing into anorexia, increasing their death risk.

Suicide is a particular risk. One in five anorexia deaths is due to suicide.

The findings show anorexia to be the most deadly psychiatric diagnosis. The anorexia mortality rate of 5.86 is dramatically higher than:

Schizophrenia, which increases death risk 2.8-fold in males and 2.5-fold in females.

Bipolar disorder, which increases death risk 1.9-fold in males and 2.1-fold in females.

Major depression, which increases death risk 1.5-fold in males and 1.6-fold in females.

People with anorexia often suffer from other psychiatric disorders. However, there wasn't enough consistent data for Arcelus and colleagues to tease out which disorders made anorexia most risky.